<!DOCTYPE html>
<html>

<head>
  <title>卡片样式</title>
  <style>
    * {
      margin: 0;
      padding: 0;
    }

    .wrap {
      width: 500px;
      margin: 30px auto;
    }

    .wrap *{
      box-sizing: border-box;
    } 
  </style>
</head>
<body>

</body>
</html>